Suitable for automobile industry, home maintenance, manufacturing and construction. characteristic: High hardness, chrome-plated treatment to resistance. Square design of four-corner arc-inner corner design of arc, with slightly inserted holes, strong locking force, not easy to slip and convenient to use. Suitable for screwdriver or electric screwdriver handle tool, which can be installed on the hexagonal handle to become a square . Allows you to match plugs, ratchet handles, extension rods and other accessories to the size of the equipment. Carbon black phosphating treatment-the is treated with carbon black phosphating treatment, which is beautiful and elegant, impregnated with antirust oil and can prevent rust., Manufacturer: Kochenty